What color is this cabbage?

I would have been thoroughly confused by the whole #TheDress meme if I hadn’t been sitting on a couch next to someone who swore she saw a white and gold dress, although she was looking at the same image on the same laptop where I saw a blue and black dress. I know from years of art history that color is not so much a basic attribute as a complex interplay of light, pigment, and perception, but it’s easy to take colors for granted, and it was fun to be reminded so strikingly that vision is a terribly subjective sense.

That experience, plus a news item about a Swedish chef who is taking his staff on an extended retreat to contemplate the color blue, among other things, reminded me of something I read about cabbages long ago.

I would call this vegetable a red cabbage. Not because I think it is red–it looks purple to me–but because that is the name it is commonly called in my region. But in parts of Germany, it’s called a blue cabbage, or blaukraut. In Portugal, it’s repolho-roxo: purple cabbage.

There may be a few different reasons for this variation in language. One is chemistry: cabbage responds to pH levels, so a cabbage of this type might grow redder leaves in acidic soil, bluer leaves in alkaline soil. This difference shows up more dramatically in cooking: red cabbage braised with even slightly basic liquid–with sugar, dairy, or alkaline water–will become blue, even greenish-blue. Vinegar or wine brings back the red tones. Thus, if southern Germany serves blaukraut for dinner but northern Germany puts rotkraut or red cabbage on the table, the differing terms might reflect differences in terrain or cooking styles for the same vegetable.

But surely, even with a heaping helping of sugar or wine, this cabbage does not become true red or pure blue. Why don’t we just call it purple, as the Portuguese do? It’s possible that the answer lies farther back in the history of those languages. Not all languages develop the same distinctions between color, or prioritize distinctions the same way–for example, there is an entire Wikipedia entry on how green and blue are or are not differentiated in different languages. The prevailing theory is that as languages evolve, they first differentiate between light and dark, then later name colors like red and yellow. Distinct words for colors like orange, purple, and pink tend to evolve even later, and not until after there is a semantic distinction between green and blue. These differences have somewhat leveled out in the global age, but many languages retain traces of earlier times when “blue” and “black” were interchangeable, or when sky and grass might be described as different shades of the same color.

So perhaps blaukraut and rotkraut linger from a time when cabbages were plentiful but words like purple, pink, and magenta were not. Perhaps these cabbages, common in Germanic and Slavic lands, didn’t show up in Portugal until that country’s kings were dying their robes roxo.

It’s interesting, though, that while I perceive this cabbage as purple, I still treat it like a red food. I cook it with other red foods like red wine, apples, and bacon. When I get red cabbage juice all over my hands, I pretend I’ve cut myself if I want to terrify my co-chefs. I never in a million years would have thought to use red cabbage to dye eggs blue. So perhaps we not only perceive colors differently on an optic level, but the language we use to differentiate and describe color may affect how we see.

I don’t know if they still make them, but for a time Wegmans had a reusable shopping bag that implored people to eat more purple foods, and red cabbage was definitely pictured as a so-called purple food.

I usually will call it red cabbage, but sometimes I do find myself calling it purple, but the next time we get a head of it I’ll be curious to see whether my store gets redder cabbage or bluer cabbage.